Gelest breaks ground on dry photoresist precursor plant

The specialty chemical maker Gelest has broken ground in Morrisville, Pennsylvania, on a commercial-scale facility that will make organometallic photoresist precursors for advanced semiconductor manufacturing. The chemicals are used to pattern nanometer-scale lines on silicon wafers with a new technique involving extreme ultraviolet (EUV) light.

For Gelest, the investment represents not just an expansion but a change in business model, according to President Jonathan Goff. “Historically, Gelest has always interacted with the electronics and semiconductor industry as more of an R&D partner,” he said at a July 7 event. Goff said the project is “a big step into being not only a new product development house but also a long-term commercial supplier to that industry.”

Goff credited Gelest’s 2020 acquisition by Mitsubishi Chemical Group for giving the firm the confidence and the business infrastructure it needed to make this move. Following the acquisition, Gelest became the center of Mitsubishi’s custom synthesis business.

When the facility opens in late 2024, its first products will be precursors needed for a new dry photoresist-based lithography technology developed by Lam Research, according to Gelest executive vice president Edward Kimble. The technique replaces a wet, solvent-based method of applying patterning chemicals to the surface of a silicon wafer with a gas-phase method based on chemical vapor deposition.

Kimble and Goff said the precursors are discrete organometallic molecules, which are more responsive to the EUV laser light used in cutting-edge semiconductor fabrication than the polymers used in wet photoresist technology. They declined to go into chemical detail about the molecules.

Goff explained that the semiconductor industry often relies on trade secrets to protect its intellectual property because the patent system is slow. The rapid pace of innovation means that getting an innovation to market quickly is more important to companies than securing long-term exclusivity on any given technology.

“You know there’s going to be others that come along that are going to do something similar, so that the key is being first, and always moving forward,” Goff said. “Before we’ve even done generation one, we’re probably already working on generation two.”

After the dry resist precursors are shipping, Kimble said, Gelest will install production lines for other chemicals it sells into markets including medical devices, vehicles, power electronics, thermal management, and specialty coatings. The firm owns an additional 3 hectares of land at the site, which leaves room for further expansions.

Lita Shon-Roy, CEO of the semiconductor supply chain consulting firm Techcet, cautions that the semiconductor industry’s move to dry photoresists is a few years off. Lam Research is facing a patent lawsuit over its technology from JSR, which bought the Lam competitor Inpria in 2021. Inpria’s main photoresist technology uses organometallic clusters with tin-oxide cores. And the equipment used to deposit and remove dry resist is currently slower than the corresponding wet resist machines.

“Perhaps pilot production in late 2024 at best, in my opinion,” Shon-Roy says.

At the same time, she says, the shift is inevitable because dry resist is shaping up to be an enabling technology to create more powerful chips. The greater precision of dry resist will produce fewer patterning errors at tiny, sub-5-nm sizes, she adds.